Synthetic thermoplastic multifilament yarns

ABSTRACT

Synthetic thermoplastic multifilament yarns with improved quality in coherency and smoothness having at most 100 twists per meter carrying about 0.5 to 3.0 percent, based on the weight of the yarns, of a treating agent comprising essentially a lubricating agent, a self-emulsifying phosphorous-containing surface active agent and a polyacrylic sizing agent, the polyacylic size being present in about 0.02 to 0.25 percent, based on the weight of the yarns.

ite -i Omura et a1;

States Patent [1 1 SYNTHETIC THERMOPLASTIC MULTIFILAMENT YARNS Inventorsf Etuzou omura; Toshio Minami;

Tetsuhiro Kusunose, all of Nobeoka, Japan Y Assignee:

Asahi Kasei Kogyo Kabushiki Kaisha, Osaka, Japan Filed:

June 19, 1972 Appl. No.: 264,104

Foreign Application Priority Data June 22, 1971 Sept. 20, 1971 Dec. 5, 1971 Dec. 5, 1971 Dec. 5, 1971 US. ci

117/138 .8 E, 117/1-38.8 N, 117/138.8 F, 117/139.5 A, 117/139.5 CQ, 252/89,

Int. C1.v

260/312 R, 260/336 UA D02g 3/36, B32b 27/02 Field ofSearch... 117/1388 N, 138.8 F, 138.8 E, [17/1395 A, 139.5 CO, 66, 7; 260/312 R, 23, 33.6 UA; 252/86, 8.9; 57/140 C, 153

POLYACRY 1 Dec. 24, 1974 [56] References Cited 1 UNITED STATES PATENTS 2,253,146 8/1941 Sprage] 117/1388 2,727,835 12/1955 Barrett 117/138.8 2,819,189 1/1958 Sucn et a1. l 117/1388 X 2,974,066 3/1961 Macura et a1 117/138.8 X 3,003,987 10/1961 Hager et a1. l17/139.5 X 3,476,581 11/1969 Weitzel et a1 l17/139.5 X 3,518,184 6/1970 Potter 117/138.8 X

3,560,382 2/1971 Finch 117/138.8 3,639,235 2/1972 Karg 252/89 Primary Examiner-William D. Martin Assistant Exantiner-Sadie L. Childs Att0rney,Agent, 0r Firm-Burgess, Dinklage & Sprung [57] ABSTRACT Synthetic thermoplastic multifilament yarns with improved quality in coherency and smoothness having at most 100. twists per meter carrying about 0.5 to 3.0 percent, based on the weight of the yarns, of a treating agent comprising essentially a lubricating agent, a selfemulsifying phosphorous-containing surface active agent and a polyacrylic sizing agent, the polyacylicsize being present in about 0.02 to 0.25 percent, based on the weight of the yarns.

9 Claims, 4 Drawing Figures PAIimiuuiazmm I $855,776

sum 1 or z POLYACRYLIC SIZING AGENT LUBRICATING AGENT PHOSPHORIC ACID ESTER LI- 0 I I I I I a 0 0.05 010 015 0.20 0.25 0.30

AMOUNT' OF POLYACYLIC SIZING AGENT ADHERING T0 YARN 1 SYNT HETIC'THERMOPLASTIC MULTIFILAMENT YARNS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a novel synthetic thermoplastic multifilament yarn having good coherency and smoothness, a treating agent and a process for producing such a yarn.

2. Description of the Prior Art At present, commonly practised methods for obtaining synthetic thermoplastic multifilaments having good coherency include steps such as imparting twist to drawn filaments or yarns or applying a viscous spinning oil or finishing oil to filaments or yarns. However, the coherency of such yarns is insufficient especially for warps. Therefore, in order to obtain good coherency of yarns an additional step such as giving at least 200 twists per meter to the yarnsor sizing the yarns prior to weaving is required. In such a sizing step polyvinyl alcohols and maleic acid copolymers are usually employed alone or in combination as the sizing agent.

Methods are already available for the omission of such twisting and sizing steps. For example, Japanese Patent 534,120describes a treating agent comprising mainly a conventional spinning oil and a melamine resin or a urea resin. Japanese Patent 576,925 refers to ethylenevinyl acetate copolymers as the treating agent. Japanese Patent 580,330 uses an emulsion of reaction products of a polyethylene with a polyolefin oxide and Japanese Patent Publication No. 15576/1969 also uses an emulsion of ethylene-acrylic acid copolymers. Thee methods all relate to the application of an emulsion of a resin and a sizing agent to filaments or yarns in the spinning process for obtaining the coherency. F urthermore, Japanese Patent Publication No. 33 19/1971 and Japanese Patent 583,530 describe rendering filaments or yarns coherent only with a spinning oil comprising mainly a wax or a glyceride, All these treating methods may omit the sizing treatment in'the spinning process but require twisting of yarns about 200 to 300 twists per meter before weaving, which disadvantageously results added in cost.

The present inventors have made extensive research on production of synthetic thermoplastic multifilament yarns or non-sized and non-twisted yarns useful as warps without any sizing and twisting treatment and initially polyacrylic sizing agents were applied to undrawn polyamide filaments or yarns and then the filaments or yarns were drawn. However, it is found the filaments or yarns thus obtained are not suitable for practical purposes because of the following disadvantages;

a. The treating agent comprising a polyacrylic sizing agent as the principal component may not be uniformly applied to undrawn filaments due to high viscosity of the emulsion.

b. The viscous materials stick to yarn-carrying devices such as guides, godet rolls and hinder the e. The treating agents sticking on undrawn filaments or yarns tend to come off in the'drawing process due to abrasion on yarn-carrying devices such as guides, feed rolls, drawing pins and drawing rolls, and hinder the travelling of filaments or yarns thereby resulting in breakage of the individual filaments and fluff after producing.

f. In the drawing process coefficients of dynamic friction of the filaments or yarns become higher than those with a conventional spinning oil and hinder the travelling of filaments or yarns thereby resulting in breakage of the individual filaments and fluff after producing.

Thus, the method of applying a sizing agent to undrawn filaments or yarns in the spinning process, i.e., before drawing, in hardly practical because of the above-described disadvantages.

Accordingly, it is a primary object of this invention to provide novel weaving warps having good coherency which completely avoid the prior art pears and cracks due to stiffness of the conventionally sized yarns and. which give improved quality textiles or fabrics.

Other objects and advantages will become apparent from the ensuing description.

THE INVENTION The present invention provide'synthetic thermoplastic multifilamentyarns of improved coherency and smoothness having at most twists per meter carrying about 0.5 to 3.0 percent, based on the weight of the yarns, of a treating agent comprising essentially a lubricating agent, a self-emulsifying phosphorus-containing surface active agent and a polyacrylic sizing agent, the polyacrylic size being present in about 0.02 to 0.25 percent, based on the weight of the yarns.

In the drawings;

FIG. I is triangular diagram, illustrative of a preferable composition of the lubricating agent, the selfemulsifying phosphorus-containing surface active agent and the polyacrylic sizing agent.

FIG. 2 is a diagram, illustrative of the relationship between the amount of polyacrylic sizing agents adhering to filaments and the fluff length on cutting a yarn.

FIG. 3 is a schematic view, illustrative of the method of measuring the fluff length, and

FIG. 4 is a schematic view, illustrative of the fluff length where the filaments of a yarn are loosened.

Examples of suitable lubricating agents to be used in this invention include mineral oils, lower alcohol esters having I to 8 carbon atoms of higher aliphatic carboxylic acids having I2 to 20 carbon atoms, higher alcohol esters having 12 to 20 carbon atoms of higher aliphatic carboxylic acids having 12 to 20 carbon atoms and mixtures thereof.

These lubricating agents may be classified broadly into two groups according to the kind of filaments or yarns to which the lubricating agents are applied. For the warping process which is operated at a rate of more than 100 meters per minute, one group includes white spindle oils, liquid paraffins, the lower alcohol esters of the higher carboxylic acids such as methyl ricinolate, methyl oleate, methyl stearate, isopropyl myristate, isopropyl palmitate, n-butyl oleate, n-butyl laurate, nbutyl stearate, expoxybutyl stearate, isoamyl stearate, n-octyl palmitate, n-octyl laurate, n-octyl oleate, noctyl stearate and mixtures thereof. The Redwood viscosity at 30C. of these lubricants is preferably in the range of from about 40 to about 100 seconds. For the warping process which is operated at a rate of 100 meters per minute or thereabout, the other group includes white spindle oils, liquid paraffins, the higher alcohol esters of the higher carboxylic acids such as lauryl laurate, tetradecyl laurate, cetyl laurate, oleyl laurate, stearyl laurate, lauryl myristylate, tetradecyl myristylate, cetyl myristylate, oleyl myristylate, stearyl myristylate, lauryl palmitate, tetradecyl palmitate, cetyl palmitate. oleyl palmitate, etearyl palmitate, lauryl stearate, tetradecyl stearate, cetyl stearate, oleyl stearate, stearyl stearate, and mixtures thereof. The Redwood viscosity at 30C. of these lubricants is preferably in the range of from about 100 to about 500 seconds.

The amount of these lubricating agents varies depending on the kind of self-emulsifying phosphoruscontaining surface active agents and polyacrylic sizing agents and of the filament or yarns to be treated and is preferably in the range of from about 5 to 68 percent on the weight of the treating agent.

Exemplary self-emulsifying phosphorus-containing surface active agents include the compounds having the following formulae;

R O(CH CH O)nP 0 onmcmomorm n oronomcmom 70H (7) OHN(CH2CH;OH)3

wowmer-rgom-P omwcmcmom;

(s) OHN(CHCH;CH:OH)3

momma-1301120 R O(CHCHaCHgO)nP=O wowncmcmom n owmcmom-p OCHCHaCHzCl RO(CHCILCH O)n-P OCHCHaCThCl 0 R o cmornom-i -ocmcrrzci R O(CHzCH2O)n R O(CHCH CHzO)n o P OCHCHaCHzCl R O(CHCH:CHzO)n R O(CHgCITzO)n PO(CHz)nCl R 0(CH CH2O)n R O(CHCH CH O)n r-ownommcl R O(CHCH CH2O)n allyl group or an allylalkyl group having'4 to 25 carbon.

atoms.

The surface active agents act as emulsifiers, cohesive agents and antistatic agents.

These self-emulsifying phosphorus-containing surface active agents are employed in an amount of about 30 to 80 percent based on theweight of the treating. Amounts of less than 30 percent by weight of the surface active agents render the emulsion of the treating agent less stable. On the other hand when the amount is more than 80 percent by weight, the viscosity of the emulsion of the treating agent remarkably increases and an even and uniform application of the treating agent to filaments or yarns becomes difficult.

It is also preferred that the hydrophilic-lipophilic balance (hereinafter referred to as HLB) of the selfemulsifying phosphorus-containing surface agent is from about 4 to 15.

The I-ILB of morethan l5 or less than 4 results in unsatisfactory emulsification of the treating agent.

The HLB is represented by a number ofO to 20. The numbers closer to 20 indicate a higher lipophilicity of the surface active agent and those closer to 20 indicate a higher hydrophilicity.

Examples of suitable polyacrylic sizing agents which may be employed in this invention include polyacrylic acid, sodium polyacrylate, lower alkyl esters of partially saponified polyacrylic acids, lower alkyl esters of partially saponified polyacrylic acid copolymers, salts of polymethyacrylic acid, polyacrylamide, acrylonitrile copolymers and saponified copolymers of vinyl acetate and a variety of acrylic monomers. The degree of polymerization of the acrylic polymers is preferably from about 100 to 2,000. The polyacrylic sizing agents should be determined according to the kind of filaments to be treated.

These polyacrylic sizing agents are used in an amount of from about 2 to about percent, and preferably from about 4 to 8 percent based on the weight of the treating agent. When the amount is less than 2 percent by weight inadequate coherency will be given to filaments or yarns. On the other hand, amounts of more than about 15 percent by weight of polyacrylic sizing agents render the viscosity of the emulsion of the treat ing agent too high to obtain an even and uniform application of the treating agent to filaments or yarns and furthermore the sizing agents adhering to the filaments or yarns come off and reduce workability.

The treating agents accordingto this invention may additionally contain antistatic agents in conventically employed amounts. 5

It is preferred that the amount of the treating agent adhering to filaments or yarns is from about 0.5 percent to 3.0 percent based on the weight of the filaments or yarns. When the amount is less than 0.5 percent by active weight, yarnshaving a desired good coherency may not be obtained. On the other hand, amounts of more than 3.0 percent by weight of the treating agent unusually increase the coefficient of friction of filaments or yarns and consequently the spinning and drawing processes cannot be smoothly operated. Furthermore, as the treating agent adhering to filaments or yarns comes off by the motion of a weavingmachine in the weaving process, the efficiency of weaving is reduced and the quality of fabrics obtained from the yarns is degraded.

Since any practical method of measuring the coherency of multifilament yarns has not been established yet, the coherency is represented by the fluff length on cutting a yarn.

On a device as illustrated in FIG. 3, a 0.5m. sample yarn 1 is set and to the end of the yarn a weight 3 of 50g. is applied. After five minute loading, the yarn is cut with scissors 2 at a point 5 cm. from the weight. Subsequently, as shown in FIG. 4, the fluff length l where the filaments of the longer yarn I are loosened is measured.

A longer fluff length indicates a power coherency and a shorter fluff length indicates a better coherency.

.In this connection, the fluff length of a conventional v sized yarn is 15mm. and that of a conventionally nonsized yarn is 130mm.

According to a general idea the coherency may be improved with increased amounts of sizing agents. On

the contrary, it has now been found that there exists an optimum range in the relationship betweenthe amount of sizing agents adhering to filaments or yarns and the coherency.

In this invention the amount of polyacrylic sizing agents adhering to filaments or yarns is preferably from about 0.02 to 0.25 percent and more preferably from about 0.075 to 0.175 percent based on the weight of the filaments or yarns. As is clear from FIG. 2, amounts of more than about 0.25 percent by weight or less than about 0.02 percent by weight of sizing agents adhering to filaments or yarns give a fluff length of 50mm. or more and thus reduce not only the coherency but also the efficiency of weaving. A more preferred fluff length of about 30mm. is obtained with amounts of about 0.075 to-0.l percent by weight of filaments or yarns. When the amount is more than about 0.25 percent by weight the coherency is decreased and furthermore the sizing agents come off on yam-carrying devices in the winding, drawing and twisting processes and workability is remarkably diminished. Even if undrawn filaments are wound up, the drawing of the filaments become impossible due to an unusual increase in the coefficient of dynamic friction of the filaments.

In order to adjust the amount of polyacrylic sizing agents adhering to filaments to the range of from about 0.02 to 0.25 percent based on the weight of the filaments or yarn it is preferred to use the treating agent in a concentration of about 10 to 25 percent by weight and a winding rate of filaments or yarns of from about 600 to 5,000 mJ/min.

Ind. co., Ltd.), which give good coherency to filaments or yarns according to this invention.

Exemplary synthetic thermoplastic materials constituting the filaments or yarns to be subjected to the treatment of this invention include polyamides, polyesters and polypropylenes.

The multifilament yarns having been treated with the treating agents according to this invention have excel lent antistatic properties and good efficiency of weaving as well as good coherency and smoothness. The textiles or fabrics obtained from the yarns are soft to the touch and free from disadvantages such as pear drops and cracks. Moreover, the yarns have excellent water resistance and are suitable not only for ordinary shuttle weaving machines but also for water-jet looms which have rapidly become popular. Scouring can also be easily effected with the yarns by choosing a sizing agent suitable for the yarns. Scouring with the yarns according to this invention is superior to that with the conventionally sized yarns which have been treated with a treating agent mainly containing a sizing agent.

The treatment with the treating agent according to this invention is effected by the conventional methods, for example, by immersing filaments or yarns in a bath of an emulsion of the treating agent or applying the treating agent to filaments or yarns with an oiling roll or a spray.

The treating agent may be uniformly applied to filaments or yarns in the filament producing processes, especially in the spinning process, but also in any process after spinning, for example, in a process with a drawing machine, a cone winder or a cheese winder prior to weaving, by the conventional methods at room temperature.

The treating agent of this invention may be employed for weaving warps as previously stated but may also be employed for weaving woofs, tricot yarns and all other yarns which require coherency. For example it is possible to apply the treating agent to modified section yarns, nep yarns, thick-and-thin yarns by an uneven drawing, conjugated yarns and other novel yarns which are generally considered inferior in coherency.

This invention will be further illustrated by the following non-limiting examples.

EXAMPLE 1 To a melt-spun, undrawn, semi-dull nylon 6 multifilament yarn consisting of 24 filaments having a denier of 210 there were independently applied to emulsions of treating agents A, B and C set forth below by rolls of spinning oil supplying devices according to an ordinary method when taken up at a rate of 1,000 meters per minute so that the amount of the treating agent adhering to the undrawn yarn was about 1.5 percent based on the weight of the yarn. After completion of the treatment the undrawn yarn was drawn 3 times by usual drawing and twisting machines and wound up on bobbins to give a multifilament yarn having 15 twists per meter and consisting of 24 filaments having a denier of 70. Then the multifilament yarns treated with the treating agents A, B and C were subjected to rough warping without another twisting and sizing, and subsequently to beaming, warp passing and water-jet looming processes. (Thus, pieces of taffets textile fabrics were obtained each having a width of 120 cm. and a length of 50 m.)

Separately, the multifilament yarn (C) was sized with a polyacrylate sizing agent by a slasher sizing machine without another twisting to give the multifilament yarn (D). Then the yarn (D) was subjected to beaming, warp passing and water-jet looming processes and 50 pieces of taffeta textile fabrics were obtained. The features of these yarns (A), (B), (C) and (D) measured in the drawing, weaving and finishing processes are set forth in Table 1.

Com osition of treating agent A according to this invention a. Liquid paraffin having a Redwood viscosity at 30C of seconds 44 weight 71 b. Alkylphosphate of polyethylene glycol ether (Trade mark: GAFAC (EB-520 made by Toho Chemical Ind. Co., Ltd.)

e. Polyacrylate sizing agent (Trade mark: PUSSIZE 208C made by Gao Chemical Ind. Co., Ltd.) 6

Composition of treating agent B according to this invention a. Liquid paraffin having a Redwood viscosity at 30C, of 250 seconds 44 weight 7( b. Alkylphosphate of polyethylene glycol ether (Trade mark: GAFAC GB-SZO" made by Toho Chemical lnd, Co.. Ltd.)

Composition of treating agent C according to a conventional method at Liquid paraffin having a Redwood viscosity at 30C of I00 seconds 60 weight 7! b. Sperm alcohol (E0) (Trade mark: AC-30l" made by Sanyo Chemical lnc. Co.. Ltd.) c. Sulfated oil of sperm alcohol 30 weight "/1 (Trade mark: AK-37" made by Kao Atlas Co, Ltd) The treating agents A, B and C, each independently were dispersed in water to obtain emulsions A, B and C with a concentration of teh treatin g agent of 16 rate of cylinder of r.p'.m. (Temperature: 20C., RH: 65 percent) 8. Gumming: The falling off of treating agent, adherweight ing to filaments or yarns due to looming motion is Table l Treatment according to conventional method Treatment acceding nonto this method sized Sized Features (A) (B) (C) Amount of treating agent 1.4 1.3 v 1.2 1.3 adhering to yarns (weight Amount of polyacrylic sizing 0.08 0.078 O 5.5 agent adhering to yarns (weight 71) Process Drawing process (1) Drawing yield (71) 98 96 95 95 (2) Fallen off materials 5 4-5 5 5 (3) Generated static elect- 2,500 2,600 2.700 2,700

ricity (V) (4) Pirn' unreeling ability 6.0 9.0 8.0 8.0

(5) Coherency (mm) 29 27 I 134 134 Weaving process (6) Coherency (mm.) 29 g 27 134 26 (7)Smoothness(;1s) 0.275 0.278 0.231 0252 do. (pd) 0.140 0.200 0.138 0.195 (8) Gumming 4-5 4-5 5 4-5 (9) Rate of weaving operation 92 93 92 (7r) Finishing process (10) Scouring ability 4-5 5 5 3-4 (1 l) Defects of weaving'warps 4-5 4-5 2-3 3-4 (12) Yield of first grade 94 95 61 90 textile fabrics (7r) Note:

1. Drawing yield Yield of first grade multifilament yarns based on all drawn multifilament yarns 2. Fallen off material: Degree of amounts of adhesives on film-forming materials which fall off from multifllament yarns on the yarn-conveying devices of drawing machine is evaluated as follows: 1: Too much accumulated for operating drawing 2: Large amount accumulated d 3: Much accumulated 4: A little accumulated but drawing not hindered 5: No fallen off material 3. Generated staticelectricity (V.): When undrawn multifilament yarns are subjected to drawing by a drawing machine at a rate of 600 meters per minute, generated static electricity at each of devices of a drawing machine such as feed rolls, drawing pins and pirns is measured bya static electricity measuring instrument made by Kasuga Electric Co., Ltd. The maximum value during the drawing is given.

4. Pirn unreeling ability (g.): Tension of unreeling 7. Smoothness: Smoothness is measured by a friction coefficient measuring device according to the Roeder method with a weight of 500 mg. at a rotating called Gumming." amounts of adhesives or filmforming materials which fall off from multifilaments yarns is evaluated as follows; -l: Accumulated too much for operating weaving 2: large amount accumulated 3: Much accumulated 4: A little accumulated but weaving not hindered 5: No gumming 9. Rate of weaving operation (percent): Rate of weaving operation from the beginning to the completion of weaving excluding the factors which are not directly related to weaving, e.g., waitingtime, etc.

10. Scouring ability: amounts of lubricating agents and polyacrylic sizing agents which are removed off during the scouring process before dyeing is evaluated as follows; i

1: No removal at all 2: Removed but much remained 3: About 50 weight percent removed and about 50 weight remained 4: A little remained and most removed 5: Completely removed 1 l. Defects of weaving warps: Degree of causing defects of weaving warps such as cracks is evaluated as follows; 1: Too much appeared for use as textile fabrics 2: Considerable defects 3: A little appeared 4: A little appeared but usable as textile fabrics 5: No defect at all 12. Yield of first grade textile fabricstpercent): To

pear drops and all woven textile fabrics the ratio of pieces which are accepted as first grade textile fabrics.

EXAMPLE 2 sisting of 24 filaments having a denier of 75. Then the multifilament yarns treated with the treating agents A, B and C were subjected to rough warping without another twisting and sizing, and subsequently to beaming, warp passing and water-jet looming. Thus 50 pieces of taffeta textile fabrics were obtained.

Separately, the multifilament yarn (C) was sized with a polyacrylate sizing agent by a slusher sizing machine without another twisting to give the multifilament yarn (D). Then the yarn (D) was subjected to beaming, warp passing and water-jet looming and 50 pieces of taffeta textile fabrics were obtained. The features of these yarns (A), (B), (C) and (D) measured in the drawing, weaving and finishing process are set forth in bins to give a yarn having twists per meter and con- 15 Table 2.

Composition of treating agent A according to this invention Octyl stearate weight 7:

Composition of treating agent B according to this invention Oleyl olcate 40 weight 7:

Alkylphosphatc of polyethylene glycol ether (Trade mark GAFAC GB-SZO" made by Toho Chemical lndv Co., Ltd.) Polyacrylate sizing agent (Trade mark MAPOZOL W-l" made by Matsumoto Oil 84 Fat Pharmaceutical Co.. Ltd.) 10

Composition of treating agent C according to a conventional method a. Liquid paraffin having a Redwood v viscosity at 30C of 130 seconds weight 71 b. Sperm alcohol (E0) (Trade mark 1 AC-301 made by Sanyo Chemical lnd. Co., Ltd.) 20 c. Sorbitan mono oleate 5 d. Sulfated oil of sperm alcohol (Trade mark AK-37 made by Kao Atlas Co.. Ltd.) 10

Table 2 Treatment according to conventional method Treatment according non- Features to this method sized Sized (A) (B) (C) (D) Amount of treating agent adhering to yarns (weight 71) 1.5 1.5 1.1 L0 Amount of polyacrylic sizing agent adhering to yarns (weight 0.15 0.15 0 6.5

Process Drawing process (1) Drawing yield (7:) 95 93 94 94 (2) Fallen off materials 4-5 4-5 5 5 (3) Generated static electricity 2,000 3.100 3,600 3,600 (4) Pirn unreeling ability (g.) 7.1 9.6 8.3 8.3 (5) Coherency (mm.) 34 27 141 14 Weaving process (6) Coherency (mm.) 34 27 141 28 (7) smoothness (#5) 0.281 0.281 0.291 0.263 do. (ad) 0.151 0.214 0.148 0.203 (8) Gumming 4-5 4 5 5 (9) Rate of weaving operation(%) 91 51 89 Finishing process (10) Scouring ability 4-5 4-5 5 3-4 (11) Defects of weaving warps 4-5 4-5 2- 3 3-4 (12) Yield of first grade textile fabrics ("/2) 94 91 71 93 EXAMPLE 3 To a melt-spun, undrawn, semi-dull nylon 6 multifilament yarn consisting of 1 7 filaments having adenier of 210 there was applied the emulsion of treating agent shown below by rolls when taken up at a rate of 1,000

' observed no falling off of the polyacrylic sizing agent adhering to the yarn and the yarn traveled very smoothly on the yarn-carrying devices. Yield of first grade multifilament yarns was 90 percent. Then the 2 multifilament yarn was subjected to rough warping process without another twisting of more than 100 twists per meter and sizing, and subsequently to beaming, warp passing and water-jet looming. Thus, 50 pieces of taffeta textile fabrics were obtained. During the weaving process there was observed no falling off of the sizing agent. Rate of weaving operation was 96 percent, and this rate was equal to or higher than that with a conventionally sized yarn. The textile fabrics thu's obtained were almost free from pear drops and cracks. Also scouring ability was good and yield of first grade textile fabrics was 91 percent, which was equal to or higher than thatwith a conventionally sized yarn.

EXAMPLE 4 To the same melt-spun, undrawn, semi-dull nylon 6 multifilament yarn as in Example 3 there was independently applied the same emulsion of treating agent as in Example 3 and the same'emulsion of treating agent C as in Example 1 by rolls when taken up at a rate of 1,000 meters per minute and subsequently the undrawn yarn was drawn 3X by ordinary drawing machines to' give a multifilament yarn consisting of 17 filaments having a denier of 70. Falling off of the treating agent occurred to a small extent during the drawing process and drawing yield was good. Then the drawn yarn was 5 given a variety of twists as set forth in Table 3. The

twisted yarns were subjected to warping process which was effected at a rate of 150 meters per minute, and further to beaming, reeling, heald passing and water-jet looming. Thus, 20 pieces of taffeta textile fabrics were 0 obtained using, as woofs, non-twisted, non-sized nylon 6 yarns consisting of 24 filaments haivng a denier 70. The results are shown in Table 3.

As is clear from Table 3, the yarns treated with the treating agent C of Example 1 according to a conventional method require at least 100 twists per meter for weaving while those treated with the treating agent of Example 3 having less than about 100 twists per meter permit weaving. In other words, the yarns according to this invention do not requiretwisting and are economically more advantageous than the non-twisted sized yarns or the twisted non-sized yarns-having at least 100 weight The treating agents was dispersed in water to obtain an emulsion having a concentration of treating agent of 16%.

twists per meter according to the conventional method. Similar results areiobtained with polyester multifilament yarns and polypropylene yarns.

Table 3 Results according to this invention Results according to the conventional method Treating Fluff Weaving Treating Fluff Weaving Number agent length on Rate of Quality agent length on Rate of Quality of adhering cutting weaving of adhering cutting weaving of twists to yarns a yarn operation woven to yarns a yarn operation woven per meter (weight 71) (mm.) (7c) fabrics (weight (mm.) (71) fabrics 0 1.2 36 92 Excellent 1.0 130 Impossible 15 1.3 33 96 do. 1.0 125 do.

30 1.2 31 93 Good 0.9 110 do.

50 1.4 28 94 Excellent 1.0 94 do.

1.3 27 91 do. 1.2 96 do. 100 1.4 29 95 Good 1.1 88 65 Poor 1.2 31 Y 94 Excellent 0.9 83 87 Good 1.3 26 95' do. 0.9 75 91 Excellent 200 1.3 24 97 do] 1.1 71 94 do. l

EXAMPLE 5 To the same melt-spun, undrawn, semi-dull nylon 6 multifilament yarn as in Example 3 there was applied become remarkable and workability is reduced. Furthermore, the coherency is gradually decreased and the rate of weaving operation is diminished. Similar results are obtained with polyester multifilament yarns and the same emulsion of treating agent as in Example 3 5 polypropylene ltifll m yams when taken "P at a rate of 1,000 meters P mlhhte by Also as is understood from Table 4, the rate of weavrOllS havlhg a Varlety of Totahhg rates so that the ing operation is kept above 90 percent only when the amount of treating agent adhering to the y was fluff length on cutting a yarn is below 50 mm. as long ied, and then t undrawn y was drawn 3X y Ordlas breakage of filaments or yarns during the drawing y drawing machines to give a muhlfhamem y l0 process is not brought about too often. Practically it is consisting of 17 filaments having a denier of 70. The d i bl h h rate f weaving i at least 90% A yarn was Subjected to warping at a ate o 150 meters cordingly, in order to obtain such high rates of weaving p m and further to beaming r g, heald p operation the maximum fluff length on cutting a yarn ing and water-jet looming. Using, as woofs, noni bo t 50 mm,

Table 4 Polyacrylic Weaving sizing agent Number of Fluff length Rate of Quality adhering breaks per on cutting weaving of to yarns Kg. of filaments a yarn operation woven (weight Workability during drawing (mm.) (/L) fabrics 0 Winding up was impossible 0.0] No problem 0.02 68 50 Poor 0.02 do. 001 50 90 Good 0.03 do. 0.03 45 92 Excellent 0.05 do. 0.02 38 96 do. 0.10 do. 0.0l 27 95 do. 015 do. 0.03 27 96 do. 0.20 do. 0.04 94 do. 0.25 Polyacrylate sizing agent slightly 0.08 50 9t Good spattered during drawing 0.30 Polyacrylate sizing agent slightly 0.56 79 45 Poor spattered during drawing 0.50 Polyacrylate sizing agent excessively l.ll I36 Impossible sputtered during drawing twisted, non-sized nylon 6 yarns consisting of 24 fila- EXAMPLE 6 ments having a denier of 70, there were obtained 20 pieces of taffeta textile fabrics. The resultsare shown The procedure of Example 5 was repeated except in Table 4. that the amount of treating agent adhering to the yarn As is clear from Table 4, there is an optimum relawas varied. The results are shown in Table 5. tionship between the amount ofpolyacrylic sizing agent As is understood from Table 5, when the amount of adhering to a yarn, the coherency and the rate of weavtreating agent adhering to yarns is less than about 0.5 ing operation. The optimum range of polyacrylic sizing weight percent it is difficult to wind up the undrawn agent is from about 0.02 to 0.25 percent based on the multifilament yarn and good coherency cannot be obweight of the yarn. When the amount is less than 0.02 weight percent, good cohesion of yarns cannot be obtained due to insufficient adhesion by the sizing agent and the rate of weaving operation is very low. On the other hand, with amounts of more than 0.25 weight tained. On the other hand, amounts of more than of 3.0 weight percent of the treating agent remarkably bring about falling off of the treating agent and workability is also remarkably reduced. Furthermore, the coherency is diminished with increased amounts of the polypercent of the sizing agent falling off of the sizing agent acrylic sizing agent.

Table 5 Treating v Weaving agent Number of Fluff length Rate of Quality adhering breaks per on cutting weaving of to yarns Kg. of filaments a yarn operation woven (weight workability during drawing (mm.) (14 fabrics 0 Winding up was impossible 0.l Winding up was rather difficult 0.05 Impossible 0.3 No problem 0.01 70 65 Poor 0.5 do. 0.03 45 92 Excellent 0.7 do. 0.04 34 94 do.

1.0 do. 0.00 31 92 do. 1.5 do. 0.0] 27 95 do. 2.0 do. 0.0l 29 93 do. 2.5 do. 0.03 27 96 do. 3.0 Small amount of treating agent adhering to yarns 0.04 35 94 Good fell off 5.0 Excessive amount of treating agent adhering to yarns 0.56 79 45 Poor fell off and wound-up yarns were deformed EXAMPLE 7 To a melt-spun, undrawn, semi-dull nylon 6 multifilament yarn consisting of 17 filaments having a denier of polyacrylic sizing agent in the treating agent is from about 4v to 8weight percent in terms of drawing and weaving. The preferred range of the alkylphosphate of polyethylene glycol ether in the treating agent is from 210 there were applied a variety of emulsions having a about 30 to 80 weight percent.

Table 6 Treating agent Number of Treating Fluff Weaving Polyacrylic Alkylphosphate breaks agent length Rate of Quality sizing Liquid of polyethylene per Kg. of adhering on cutting weaving of agent paraffin glycol ether filaments to yarns a yarn operation woven (weight (weight (weight workability during (weight 70) (mm.) (7:) fabrics drawing 0 40 60 No problem 0.0] 1.4 61 Impossible 2 4O 58 do. 002 1.3 53 87 Good 4 40 56 do. 0.03 1.5 34 93 Excellent 6 40 54 do. 0.06 1.4 28 95 do. 8 40 52 do. 009 1.3 38 96 do. 10 40 50 do. 0.07 1.6 48 90 Good 40 45 Polyacrylate sizing agent 0.12 1.6 52 85 do.

slightly sputtered during drawing 20. 40 40 Polyacrylate sizing agent 7.30 1.9 75 Impossible excessively sputtered during drawing 6 74 Emulsification was too poor for use 6 64 Emulsification was 0.01 1.3 34 90 Excellent slightly poor but usable 6 54 No problem 0.01 1 2 30 96 do. 6 44 do. 0.02 1.4 33 95 do. 6 34 do. 0.03 I 1.6 29 92 Good 6 24 do. 0.00 1.7 27 91 Excellent 6 14 viscosity of emulsion was 0.06 1 9 25 89 do.

' slightly high but usable 6 4 90 Viscosity of emulsion was too high for use Polyacrylic sizing agent: Trade mark. "PLUSSlZE 208C" made by Gao Chemical Ind. Co., Ltd. Liquid paraffin having a Redwood viscosity at 30C. of 250 seconds Alkylphosphate of polyethylene glycol ether: Trade mark. GAFAC GBSZO" made by Toho Chemical 1nd. Co. Ltd.

concentration of the treating agent of 16 weight per- EXAMPLE 8 cent set forth in Table 6 by rolls when taken up at a rate of 1,000 meters per minute and the undrawn yarn was drawn 3X by ordinary drawing and twisting machines to give a multifilament yarn having 15 twists per meter and consisting of 17 filaments having a denier of 70. Then the drawn multifilament yarn was subjected to warping which was effected at a rate of meters per minute, without sizing, and further to beaming, reeling, heald passing and water-jet looming. Using, as woofs, non-twisted, non-sized nylon 6 yarns having 24 filaments having a denier of 70, there were obtained 20 pieces of taffeta textile fabrics. The results are shown in Table 6.

As in clear from Table 6 the optimum range of the Tr'eating agent The procedure of Example 7 was repeated except that a variety of emulsions having a concentration of the treating agent of 16 weight percent set forth in Table 7 were employed. The results are shown in Table 7. s

As is shown in Table 7 the coherency does not vary much even when the Redwood viscosity of the liquid paraffin is changed from 40 to 500 seconds and the kinds of self-emulsifying phosphorus-containing surface active agents and polyacrylic sizing agents are changed. Multifilament yarns having a fluff length of less than about 50 mm. can be easily obtained from such treating agents as set forth in Table 7.

Table 7 Lubricating agent Treating I 44' weight agent Fluff length Liquid viscosity having Self-emulsifying Polyacrylic adhering. on a Redwood viscosity at 30C. 1 surface active agent sizing agent to yarns cutting yarn (second) 50 weight 7: 6 weight (weight 71) (mm.)

40 GAFAC GB-520 *1 PLUSSIZE .l "8 1.4 '39 80 do. do. 1.5 37 150 do. do. 1.3 35 250 do. do. 1.6 28 300 do. do. 1.5 27 500 do. do. 1.4 24 150 TLHOSPHAC L-6"*2 do. 1.4

Table 7-Continued Treating agent Lubricating agent Treating 44 weight 7: agent Fluff length Liquid viscosity having Selfemulsifying Polyacrylic adhering on 11 Redwood viscosity at 30C. surface active agent sizing agent to yarns cutting yarn (second) 50 weight 7! 6 weight 7: (weight '7() (mm.)

do. PHOSPHAC O-8*3 do. 1.5 35 do. GAFAC RS-61()*4 do. 1.5 28 do. GAFAC LO-529"* do. 1.4 31 do. GAFAC RD-52OY""6 do. 12 28 do. GAFAC RD-720*7 do. 29 do. GAFAC GB-520" NAPS-2") 1.3 24 do. do. Sodium polyacrylate 1.4 38

having a degree of polymerization of 900* 10 150 GAFAC (EB-520" PLUSSIZE 208C"*11 1.5 36 do. do. MAPOZOL W-1"12 1.4 32 do. do. MAPOZOL W-6*13 1.5 do. do. MAPOZOL 1.3 27

*1 Trade mark :GAFAC (PB-520". made by Toho Chemical lnc. Co., Ltd. *2 do. :PHOSPHAC L-6" (triphosphate. R=C n=6), made by Toho Chemical lnc. Co., Ltd. *3 do. :PHOSPHAC O-8( do. R=C,,,. n=8), do. *4 do. GAFAC RS-6l0" (mixture of monophosphate and diphosphnte. R=C, n=6) do. *5 do. GAFAC LO-529" do. R=nonylphenyl, n=6). do. *6 do. :GAFAC RD-520Y"( do. R=C n=4), do. *7 do. :GAFAC RD-720( do. R=C n=7) do. *8 do. PLUSSlZE .1 (polyacrylate copolymer). made by Matsumoto Oil & Fat Phermaceutical Co.. Ltd. *9 do. NAPS-2 (polyacrylic acid), do. *10 do. made by Katayama Chemical 1nd. Co.. Ltd. *1 1 do. PLUSSIZE 208C (polyacrylate copolymer), do. *12 do. :MAPOZOL W-1"( do. do. 13 do. :MAPOZOL W-6( do. do. *14 do. :MAPOZOL W-412( do. do.

EXAMPLE 9 devices. Yield of first grade multifilament yarns was 95 To a melt-spun, undrawn, semi-dull nylon 6, 6 multifilament yarn consisting of 24 filaments having a denier of 210 there were independently applied the emulsions of treating agents A and B set forth below by rolls according to an ordinary method when taken up at a rate of 1,000 meters per minute so that the amount of the treating agent adhering to the undrawn yarn was about 1.5 percent based on the weight of the yarn. After completion of the treatment the wound-up, undrawn yarn was drawn 3 by usual drawing and twisting machines and wound up on bobbins to give a multifilament yarn having 15 twists per meter and a fluff length of 34 mm. (according to the treating agent A) and 35 mm. (according to the treating agent B), respectively and consisting of 24 filaments having a denier of 70. During the above-described spinning, winding-up, drawing and twisting processes, there was observed no falling off of the polyacrylic sizing agent adhering to the yarn and the yarn traveled very smoothly on the yarn-conveying percent (according to the treating agent A) and 93 percent (according to the treating agent B), respectively. Then the multifilament yarn was subjected to rough warping process without another twisting of more than twists per meter and sizing, and subsequently to beaming, warp passing and water-jet looming to give 50 pieces of taffeta textile fabrics. During the weaving process there was no falling off of the sizing agent. Rate of weaving operation was 92 percent (according to the treating agent A) and 93 percent (according to the treating agent B), respectively, and the rate was equal to or higher than that with a conventionally sized yarn. The textile fabrics thus obtained were almost free from pear drops and cracks and scouring ability was good. Yield of first grade textile fabrics was 91 percent (according to the treating agent A) and 93 percent (according to the treating agent B), respectively, which was equal to or higher than that with a conventionally sized yarn.

Treating agent A Oleyl oleate 40 weight 7:

Treating agent B The same as in treating agent A 40 weight 7t Alkylphosphate of polyethylene glycol ether having a HLB of 6.9

(Trade mark GAFAC (EB-520" made by Toho Chemical lnc. Co..Ltd.) 50

The same as in treating agent A 21 The treating agents A and B, each independently dispersed in water to obtain emulsions A and B having a concentration of the treating agent of 16 weight COMPARATIVE EXAMPLE 1 chines, and wound up on bobbins to give a multifilament yarn consisting of 17 filaments having a denier of 70 and having 15 twists per meter and a fluff length on cutting a yarn of 90 mm. with the treating agent A and 93 mm. with the treating agent B. During the spinning, winding-up, drawing and twisting processes, the sizing agent fell off much from the yarn and yield of first grade multifilament yarns was only l4 percent with the treating agentA. On the other hand, with the treating agent B there was observed no falling off of the sizing agent during these processes and yield of first grade multifilament yarns was'90 percent. However weaving was impossible with yarns treated with the treating agents A and B without twisting of more than 100 twists per meter or without ordinary sizing.

Treating agent A a. Liquid paraffin having a Redwood viscosity at 30C. of 25 seconds 30 weight b. Alkylphosphate of polyethylene glycol ether having a HLB of 6.9

(Trade mark 2 GAFAC GB-520 made by Toho Chemical lnd. Co., Ltd. 30

c. Alkylimidazoline (Trade mark ELECTROSTRIPPER C made by Kao Atlas Co., Ltd.) 5 d. Polylacrylate sizing agent (Trade mark PLUSSIZE 208C made by Gao Chemical lnd. Co., Ltd.) 35

Treating agent B I a. Liquid paraffin having a Redwood viscosity at 30C. of 250 seconds 60 b. Polyoxyethylene glycerine ester (Polyoxyethylene 25 moles) (Trade mark .K-l 161" made by Kao Atlas Co., Ltd.) 29

c. Alkylimidazoline (Trade mark ELECTROSTRIPPER C" made by Kao Atlas Co.. Ltd.) 5 d. Polyacrylate sizing agent (Trade mark PLUSSIZE 208C" made by Gao Chemical lnd. Co., Ltd.) 6

The treating agents A and B, each independently, dispersed in'water to obtain emulsions A and B having a concentration of the treating agent of 16 weight EXAMPLE To a melt-spun, undrawn polyethylene terephthalate consisting of 24 filaments having a denier of 225 there was applied the emulsion of treating agent shown below by rolls when taken up at a rate of 1,000 meters per minute so that the amount of the treating agent adhering to the undrawn yarn was 1.6 percent based on the weight of the yarn. After completion of the treatment, the wound-up, undrawn yarn was hot drawn 3 X by ordinary drawing and twisting machines, and wound up on bobbins to give a multifilament yarn having 15 twists per meter and consisting of 24 filaments having denier of 75. During the above-described spinning, windingup, drawing and twisting processes there was observed no falling off of the polyacrylic sizing agent adhering to the yarn and the yarn traveled very smoothly on the yarn-conveying devices. Yield of first grade multifilament yarns'was percent. Then the multifilament yarn was subjected to rough warping without another twisting of more than twists per meter and sizing,

Treating agent Weight a. Trimethylolpropane tridecanoate 40 b. Alkylphosphate of polyethylene glycol ether (Trade mark GAFAC (EB-520" made by Toho Chemical lnd. Co., Ltd.) 50

c. Alkylphosphate (Trade mark A72 made by Takemoto Oil and Fat Co., Ltd.) 5 d. Polyacrylate sizing agent 0 (Trade mark "MAPOZOL W-l" made by Matsumoto Oil & Fat Pharmaceutical Co., Ltd. 5

The treating agent was dispersed in water to abtain an emulsion having a concentration of the treating agent of 16 weight EXAMPLE 1 1 To a melt-spun, undrawn nylon 6 multifilament yarn consisting of 17 filaments having a denier of 210 there was applied the emulsion-of treating agent set forth below by oiling rolls so that the amount of the treating agent adhering to the undrawn yarnwas 1.6 percent based on the weight of the yarn. Then the yarn was drawn 3X by a conventional'method. The fluff length on cutting the resulting drawn multifilament yarn consisting of 17 filaments having a denier of 70 is shown in Table 8, which indicates high coherency.

Treating agent weight a. Mineral oil having a Redwood viscosity at 30C. of 150 seconds b. Alkylphosphate of polyethylene glycol ether (Polyoxyethylene 7 moles) (Trade mark PLSSlZE 208 C" made by Gao Chemical lnd. Co., Ltd.) c. Polyacrylic acid having a degree of polymerization of 1000 6 d. Alkylimidazoline (Trade mark ELECTROSTRIPPER C" made by Kao Atlas Co, Ltd.) 4

The treating agent was dispersed in water to obtain an emulsion having a concentration of the treating agent of 16 weight Table 8 Fluff length cutting a Yarns yarn(mm.) Remarks Yarns according to this 28 invention Yarns according to a [33 Treated with the conventional method emulsion without the phosphate and the polyacrylic sizing agent Sized yarns l4 Treated only with the polyacrylic acid sizing agent Yarns according to the 90 method disclosed in Japanese Patent Publication No.33l9/l97l EXAMPLE 12 To a melt-spun, undrawn nylon 6,6 multifilament yarn consisting of 24 filaments having a denier of 210 there was applied the emulsion of treating agent set forth below by oiling rolls so that the amount of the treating agent adhering to the undrawn yarn was 1.6 percent based on the weight of the yarn. Then the undrawn yarn was drawn 3X by a conventional method. The fluff length on cutting the resulting drawn multifilament yarn consisting of 24 filaments having a denier of 70 is shown in Table 9, which indicates high coherency.

weight Treating agent a. Mineral oil having a Redwood viscosity at 30C. of [50 seconds b. Butyl stearate 20 c Alkylphosphate of polyethylene glycol 'ether (Polyoxyethylene 7 moles) (Trade mark PLUSSlZE 208 C made by Ciao Chemical lnd. Co.. Ltd.) 50

d. Polyacrylic acid having a degree of polymerization of 1,000 6 e. Sulfated sperm oil (Trade mark AK-37" made by Kao Atlas Co., Ltd.) 4

. 6 The treating agent was dispersed in water to obtain an emulsion having a concentration of the treating agent of 16 weight To a melt-spun, undrawn polyethylene terephthalate multifilament yarn consisting of 24 filaments having a denier of l there was applied the emulsion of treating agent set forth below by oiling rolls so that the amount of treating agent adhering to the undrawn yarn was 1.6 percent based on the weight of the yarn. Then the yarn was hot drawn 3.5X by a conventional method. The fluff length on cutting the resulting drawn multifilament yarn consisting of 24 filaments having a denier of 50 is shown in Table 10, which indicates high coherency.

Table 10 Fluff length cutting a yarn Yarns (mm.) Remarks Yarns according to this 30 invention Yarns according to a I28 Treated with the conventional method emulsion without the phosphate and the polyacrylic sizing agent Sized yarns l9 Treated only with the polyacrylic acid sizing agent Yarns according to the 93 method disclosed in Japanese Patent Publication Nov33l9/l97l Treating agent weight a. Mineral oil having a Redwood viscosity at 30C. of 300 seconds b. Oleyl oleate c. Alkylphosphate of polyethylene glycol ether (Polyoxyethylene 7 moles) (Trade mark PLUSSIE 208C" made by Gao Chemical lnd. Co.. Ltd.) d. Polyacrylic acid having a degree of Polymerization of L000 8 e. Alkylphosphate (Trade mark A-72" made by Takemoto Oil & Fats Co., Ltd.) 7

The treating agent was dispersed in water to obtain an emulsion having a concentration of treating agent of 16 weight What is claimed is: 1. A synthetic thermoplastic multifilament yarn having at most 100 twists per meter carrying about 0.5 to

5 3.0 percent, based on the weight of the yarn, of a treating agent comprising about 5 to 68 percent by weight of a liquid, synthetic yarn lubricating agent, about 30 to percent by weight of a self-emulsifying organic phosphorus-containing surface active agent having a HLB of from about 4 to and about 2 to 15 percent by weight of a polyacrylic sizing agent, the polyacrylic size being present in about 0.02 to 0.25 percent, based on the weight of the yarn.

2. The synthetic thermoplastic multifilament yarn of claim 1 wherein the amount of the polyacrylic sizing agent adhering to the yarn is from about 0.075 to 0.175 percent based on the weight of the yarn.

3. The synthetic thermoplastic multifilament yarn of claim 1 wherein the amount of the polyacrylic sizing agent in the treating agent is about 4 to'8% by weight.

4. The synthetic thermoplastic multifilament yarn of claim 1 wherein said treating agent additionally contains an antistatic agent,

5. A process for producing synthetic thermoplastic multifilament yarns having improved coherency and smoothness which comprises, prior to drawing, treating undrawn synthetic thermoplastic rnultifilament yarns with a treating agent comprising about 5 to 68 percent by weight of a liquid, synthetic yarn lubricating agent, about 30 to 80 percent by weight of a self-emulsifying organic phosphorus-containing surface active agent having a HLB of from about 4 to 15 and about 2 to 15 percent by weight of a polyacrylic sizing agent so that the amount of said treating agent adhering to said yarns is from about 0.5 to 3.0 percent based on the weight of the yarns and the amount of said polyacrylic sizing agent adhering to said yarns is from about 0.02 to 0.25 percent based on the weight of the yarns, and thereafter hot drawing and winding said yarns.

6. The process of claim 5 wherein the treating agent contains additionally an antistatic agent.

7. The process of claim 5 wherein the treating agent is employed in the form of a dispersion in water with a concentration of said treating agent being from about 10 to 25 percent by weight.

8. The process of claim 7 wherein the dispersion in -water is applied to the undrawn multifilament yarns' which is being taken up at a rate of from about 600 to 5,000 meters per minute.

9. The process of claim 8 wherein the synthetic thermoplastic material constituting said yarn is polyamide, polyester or polypropylene. 

1. A SYNTHETIC THERMOPLASTIC MULTIFILAMENT YARN HAVING A MOST 100 TWISTS PER METER CARRYING ABOUT 0.2 TO 3.0 PERCENTT
 2. The synthetic thermoplastic multifilament yarn of claim 1 wherein the amount of the polyacrylic sizing agent adhering to the yarn is from about 0.075 to 0.175 percent based on the weight of the yarn.
 3. The synthetic thermoplastic multifilament yarn of claim 1 wherein the amount of the polyacrylic sizing agent in the treating agent is about 4 to 8% by weight.
 4. The synthetic thermoplastic multifilament yarn of claim 1 wherein said treating agent additionally contains an antistatic agent.
 5. A process for producing synthetic thermoplastic multifilament yarns having improved coherency and smoothness which comprises, prior to drawing, treating undrawn synthetic thermoplastic multifilament yarns with a treating agent comprising about 5 to 68 percent by weight of a liquid, synthetic yarn lubricating agent, about 30 to 80 percent by weight of a self-emulsifying organic phosphorus-containing surface active agent having a HLB oF from about 4 to 15 and about 2 to 15 percent by weight of a polyacrylic sizing agent so that the amount of said treating agent adhering to said yarns is from about 0.5 to 3.0 percent based on the weight of the yarns and the amount of said polyacrylic sizing agent adhering to said yarns is from about 0.02 to 0.25 percent based on the weight of the yarns, and thereafter hot drawing and winding said yarns.
 6. The process of claim 5 wherein the treating agent contains additionally an antistatic agent.
 7. The process of claim 5 wherein the treating agent is employed in the form of a dispersion in water with a concentration of said treating agent being from about 10 to 25 percent by weight.
 8. The process of claim 7 wherein the dispersion in water is applied to the undrawn multifilament yarns which is being taken up at a rate of from about 600 to 5,000 meters per minute.
 9. The process of claim 8 wherein the synthetic thermoplastic material constituting said yarn is polyamide, polyester or polypropylene. 